This invention relates to an installation for winning material from a mineral face in a mine working. The invention is particularly concerned with a plough for use in mining coal.
Known coal ploughs are arranged to be driven along a guide which is provided at the coal face side of a conveyor such as a scraper-chain conveyor. Such a plough is provided with a loading ramp for loading the won coal onto the conveyor. Passages are provided, behind the guide, for the endless plough drive chain. On the mine floor, the guide has a floor plate which forms a slide path for the plough and which also serves to limit the depth of cut of the plough. For this purpose, the arrangement is such that the plough cutters project, to an extent equal to the required depth of cut, beyond the front edge of the guide, that is to say of its floor plate, this edge being pressed against the coal face to be won.
In known coal ploughs, the cutters adjacent to the mine floor perform the function of carrying out a cut of predetermined depth in the floor zone immediately in front of the front edge of the floor plate, this cut being utilised for control or stress-relieving purposes. Since the plough has to be moved along its guide with a relatively large amount of play, and as the floor cutters are arranged on the body of the plough, each movement of this body relative to the guide necessarily leads to a change in the position of the floor cutters during their cutting action. Obviously, this is undesirable and can result in operational difficulties. In particular, when hard coal is being won, if the floor cutters are advanced too far, a considerable increase in the tensile forces in the plough chain will occur which may even cause the plough to become jammed.